Disk drives are information storage devices that utilize at least one rotatable disk with concentric data tracks containing the information, a head or transducer for reading data from or writing data to the various tracks, and a head positioning actuator connected to the head for moving it to the desired track and maintaining it over the track during read and write operations. The head is fabricated in an air-bearing slider, which is supported adjacent to the data surface of the disk by a cushion of air generated by the rotating disk. The head can also be attached to a contact recording type slider. In either case, the slider is connected to a support arm of the transducer-positioning actuator by means of a suspension.
As disk drives have become smaller in size and higher in capacity, the recorded track density has increased dramatically. This has necessitated the use of magnetic recording heads with smaller and smaller critical dimensions in both reader and writer heads to generate and read narrower data tracks. However, these smaller geometries of the head make manufacture much more difficult as performance and design requirements are increasingly precise. Under conventional methods heads are tested under fixed test conditions after they have been mounted on to a Head Gimbal Assembly (herein HGA).
Testing under fixed test conditions, which deviates from drive format and test conditions, presents at least two problems: 1) missing bad parts during screening, 2) rejection of good parts. First, all bad heads need to be screened out as completely to reduce costs. Bad heads that escape the screening process result in loses as a result of reduce costs. Bad heads that escape the screening process result in loses as a result of defective hard drives. Second, the number of good parts that are rejected needs to be minimized in order to keep costs down. Any good part that is incorrectly rejected results in increased overall head cost. Additionally, long test times result in substantial costs and testing often requires labor time as well the costly equipment